• Safety and Health at Work
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• 제2권1호
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• pp.17-25
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• 2011

Objectives: In this study, the in vitro mammalian chromosomal aberration (CA) assay was conducted to gain additional information concerning the hazards associated with the use of cyclopentane and ammonium nitrate. While these two chemicals had already been tested by many methods, they had not been studied in the CA test. Methods: The assay was performed using the ovarian infantile cell (CHO-K1 cell), by the direct method (-S9) and by the metabolic activated method (+S9 mix). Results: Using the direct method, the 7 dosages in a 48 hour treatment group did not show that the frequency of CA is proportion to the dosage addition. The frequency of CA is not proportion to the dosage addition for a 6 hour treatment using the metabolic activated method. Conclusion: From these findings, it was decided that the 2 chemicals do not induce chromosomal aberrations under the tested conditions.

• 한국토양비료학회지
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• 제49권6호
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• pp.655-661
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• 2016

Relationships between saturated conductivity (Ks) and separate contents were evaluated from 44 soil series of arable lands: 18 for paddy fields and 26 for upland crop fields. Saturated hydraulic conductivities of A, B, and C horizons were determined with tension infiltrometer and Guelph permeameter in situ. Sand, silt, clay, and organic matter content of each horizon were analyzed. Based on correlation analysis, sand separate had a positive relationship with Ks for both paddy (r=0.27, p=0.017) and upland fields (r=0.24. p=0.030). Clay content had a negative relationship with Ks for paddy soils (r=-0.32, p=0.005) while significant correlation between them was not found for upland crop fields (r=-0.20, p=0.07). Organic matter content showed a positive relationship with Ks only for upland crop fields (r=0.33, p=0.002). Due to low correlation coefficients between separate contents and Ks, performance of pedotransfer functions was not enough to estimate Ks. It implies that hydraulic properties of arable lands were affected by other factors rather than particle characteristics. Platy structure and plow pan were suggested to limit Ks of paddy fields. Soil compaction and diversity of parent materials were proposed to influence Ks of upland crop fields. It suggests that genetic processes and artificial managements should be included in pedotransfer functions to estimate hydraulic properties appropriately.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8093-8100
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• 2016

Background: Genetic and environmental factors play important roles in pathogenesis of digestive tract cancers like those in the esophagus, stomach and colorectum. Folate deficiency and methylenetetrahydrofolate reductase (MTHFR) as an important enzyme of folate and methionine metabolism are considered crucial for DNA synthesis and methylation. MTHFR variants may cause genomic hypomethylation, which may lead to the development of cancer, and MTHFR gene polymorphisms (especially C677T and A1298C) are known to influence predispositions for cancer development. Several case control association studies of MTHFR C677T polymorphisms and colorectal cancer (CRC) have been reported in different populations with contrasting results, possibly reflecting inadequate statistical power. Aim: The present meta-analysis was conducted to investigate the association between the C677T polymorphism and the risk of colorectal cancer. Materials and Methods: A literature search of the PubMed, Google Scholar, Springer link and Elsevier databases was carried out for potential relevant articles. Pooled odds ratio (OR) with corresponding 95 % confidence interval (95 % CI) was calculated to assess the association of MTHFR C677T with the susceptibility to CRC. Cochran's Q statistic and the inconsistency index (I2) were used to check study heterogeneity. Egger's test and funnel plots were applied to assess publication bias. All statistical analyses were conducted by with MetaAnalyst and MIX version 1.7. Results: Thirty four case-control studies involving a total of 9,143 cases and 11,357 controls were retrieved according to the inclusion criteria. Overall, no significant association was found between the MTHFR C677T polymorphism and colorectal cancer in Asian populations (for T vs. C: OR=1.03; 95% CI= 0.92-1.5; p= 0.64; for TT vs CC: OR=0.88; 95%CI= 0.74-1.04; p= 0.04; for CT vs. CC: OR = 1.02; 95%CI= 0.93-1.12; p=0.59; for TT+ CT vs. CC: OR=1.07; 95%CI= 0.94-1.22; p=0.87). Conclusions: Evidence from the current meta-analysis indicated that the C677T polymorphism is not associated with CRC risk in Asian populations. Further investigations are needed to offer better insight into any role of this polymorphism in colorectal carcinogenesis.

• Asian Pacific Journal of Cancer Prevention
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• 제16권11호
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• pp.4521-4524
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• 2015

Background: Endometrial carcinoma is the most common malignant tumor of the female genital tract and the fourth most common cancer in Iranian women after breast, colorectal and lung cancers. Various genetic alterations appear to be early events in the pathogenesis of endometrial carcinoma and it seems that PTEN is the most commonly mutated gene in the endometrioid subtype. The aim of the present study was to investigate the correlation between mutations in exon 7 of PTEN gene and endometrial carcinoma. Materials and Methods: Seventy-five patients with endometrial carcinoma and 75 females whose underwent hysterectomy for non tumoral indication were selected for evaluation of PTEN mutations in exon 7 by PCR-SSCP and sequencing. Correlations between the frequency and type of mutation and the pathologic findings of the cancer (tumor subtype, stage and grade) were assessed. Results: All of the samples were obtained from Iranian patients. 60 % (45 cases) of the tumors were endometriod and 40% (30 cases) were of serous type. The grade distributions of the 75 cases according to the FIGO staging system were as follows: low grade, 20 cases; high grade 55 cases, low stage, 41 cases; high stage 34 cases. For exon 7 of the PTEN gene, the analysis showed that there were no mutations in our cases. Conclusions: Our findings in the present study suggest that exon 7 of PTEN does not play any significant role in the development of endometrial carcinoma in Iranian cases.

• 전자공학회논문지
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• 제51권5호
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• pp.51-57
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• 2014

본 논문에서는 M-ary 홀로그래픽 데이터 저장장치에 적용 가능한 진화 연산 알고리즘 기반 적응적 문턱치 검출 기법을 제안한다. 전통적으로 유전 알고리즘은 생명체의 유전자 진화과정에 근간하여 최적 혹은 준최적 문제와 데이터 추정을 위해 사용되는 매우 유용한 기법이다. 본 연구에서는 픽셀 어긋남이 심화되는 2차원 홀로그래픽 채널 환경에서 데이터의 검출 성능을 향상시키기 위해서, 각 데이터 검출 영역의 문턱 값(threshold value)을 유전 알고리즘의 인구 집합(population set)의 해로 간주하여 비트 검출 영역을 적응적으로 선택하는 방법을 제안한다. 제안하는 기법의 성능을 평가하기 위해 픽셀 어긋남 현상이 심화된 4-ary 멀티레벨 입력의 홀로그래픽 채널 환경을 고려하고 모의실험을 수행하여 진화 연산의 세대수에 따른 비트오율 성능을 측정한다. 성능평가를 통해 기존의 비트 검출 기법과 비교함으로써 제안 기법의 우수성을 확인하였다.

• 한국지능시스템학회논문지
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• 제7권2호
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• pp.16-24
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• 1997

본 논문에서는 각각의 유전자 개체가 그 자신의 나이를 갖는 수정된 유전자 알고리즘을 제안한다. 그래서 하나의 개체는 그 자신의 나이가 0이 되었을때 만이 사라지게 되며, 결국 개체들의 수가 동적으로 증가할 것이다. 이러한 방법은 좋은 특성을 갖는 유전자들을 그들의 적합도에 상응하게 매겨진 나이에 따라서 몇세대에 걸쳐 살아있게 함으로서 그들의 좋은 형질을 좀더 보존할 수 있는 능력을 유전자 알고리즘이 갖추게 만든다. 그러므로, 이러한 방법은 기존의 방법보다 더욱 좋은 성능을 내게 된다.우리는 이 방법을 실험하기 위하여 함수최적화 문제를 이용하여 시뮬레이션하였다. 제안한 방법의 효율성을 보이기 위하여, 세가지의 나이를 먹는 방식을 제안하였다. 본 논문의 아이디어와 유사한 연구논문이 있었는데, 이 연구에서 성능이 가장 좋은 방식을 채택하여 실험하였다. 또한 원래의 간단한 유전자 알고리즘도 실험을 하여 성능을 비교 하였다. 그러나, 기존의 방식은 나이를 산정할때 적합도롤 고려하지 않음으로서 본 논문에서 제안한 방식보다 몇몇 측면에서 성능이 좋지 않았다.

• The Journal of Advanced Prosthodontics
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• 제6권2호
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• pp.96-102
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• 2014

PURPOSE. This study was performed to characterize the effects of zirconia coated with calcium phosphate and hydroxyapatite compared to smooth zirconia after bone marrow-derived osteoblast culture. MATERIALS AND METHODS. Bone marrow-derived osteoblasts were cultured on (1) smooth zirconia, (2) zirconia coated with calcium phosphate (CaP), and (3) zirconia coated with hydroxyapatite (HA). The tetrazolium-based colorimetric assay (MTT test) was used for cell proliferation evaluation. Scanning electron microscopy (SEM) and alkaline phosphatase (ALP) activity was measured to evaluate the cellular morphology and differentiation rate. X-ray photoelectron spectroscopy (XPS) was employed for the analysis of surface chemistry. The genetic expression of the osteoblasts and dissolution behavior of the coatings were observed. Assessment of the significance level of the differences between the groups was done with analysis of variance (ANOVA). RESULTS. From the MTT assay, no significant difference between smooth and surface coated zirconia was found (P>.05). From the SEM image, cells on all three groups of discs were sporadically triangular or spread out in shape with formation of filopodia. From the ALP activity assay, the optical density of osteoblasts on smooth zirconia discs was higher than that on surface treated zirconia discs (P>.05). Most of the genes related to cell adhesion showed similar expression level between smooth and surface treated zirconia. The dissolution rate was higher with CaP than HA coating. CONCLUSION. The attachment and growth behavior of bone-marrow-derived osteoblasts cultured on smooth surface coated zirconia showed comparable results. However, the HA coating showed more time-dependent stability compared to the CaP coating.

• BMB Reports
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• 제39권5호
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• pp.492-501
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• 2006

Since differentiation therapy is one of the promising strategies for treatment of leukemia, universal efforts have been focused on finding new differentiating agents. In that respect, we used guanosine 5'-triphosphate (GTP) to study its effects on K562 cell line. GTP, at concentrations between 25-200 ${\mu}M$, inhibited proliferation (3-90%) and induced 5-78% increase in benzidine-positive cells after 6-days of treatments of K562 cells. Flow cytometric analyses of glycophorine A (GPA) showed that GTP can induce expression of this marker in more mature erythroid cells in a time- and dose-dependent manner. These effects of GTP were also accompanied with inhibition of DNA synthesis (measured by [$^3H$]-thymidine incorporation) and early S-phase cell cycle arrest by 96 h of exposure. In contrast, no detectable effects were observed when GTP administered to unstimulated human peripheral blood lymphocytes (PBL). However, GTP induced an increase in proliferation, DNA synthesis and viability of mitogen-stimulated PBL cells. In addition, growth inhibition and differentiating effects of GTP were also induced by its corresponding nucleotides GDP, GMP and guanosine (Guo). In heat-inactivated medium, where rapid degradation of GTP via extracellular nucleotidases is slow, the anti-proliferative and differentiating effects of all type of guanine nucleotides (except Guo) were significantly decreased. Moreover, adenosine, as an inhibitor of Guo transporter system, markedly reduced the GTP effects in K562 cells, suggesting that the extracellulr degradation of GTP or its final conversion to Guo may account for the mechanism of GTP effects. This view is further supported by the fact that GTP and Guo are both capable of impeding the effects of mycophenolic acid. In conclusion, our data will hopefully have important impact on pharmaceutical evaluation of guanine nucleotides for leukemia treatments.

• Toxicological Research
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• 제32권4호
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• pp.289-300
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• 2016

Non-genotoxic carcinogens are substances that induce tumorigenesis by non-mutagenic mechanisms and long term rodent bioassays are required to identify them. Recent studies have shown that transcription profiling can be applied to develop early identifiers for long term phenotypes. In this study, we used rat liver expression profiles from the NTP (National Toxicology Program, Research Triangle Park, USA) DrugMatrix Database to construct a gene classifier that can distinguish between non-genotoxic carcinogens and other chemicals. The model was based on short term exposure assays (3 days) and the training was limited to oxidative stressors, peroxisome proliferators and hormone modulators. Validation of the predictor was performed on independent toxicogenomic data (TG-GATEs, Toxicogenomics Project-Genomics Assisted Toxicity Evaluation System, Osaka, Japan). To build our model we performed Random Forests together with a recursive elimination algorithm (VarSelRF). Gene set enrichment analysis was employed for functional interpretation. A total of 770 microarrays comprising 96 different compounds were analyzed and a predictor of 54 genes was built. Prediction accuracy was 0.85 in the training set, 0.87 in the test set and increased with increasing concentration in the validation set: 0.6 at low dose, 0.7 at medium doses and 0.81 at high doses. Pathway analysis revealed gene prominence of cellular respiration, energy production and lipoprotein metabolism. The biggest target of toxicogenomics is accurately predict the toxicity of unknown drugs. In this analysis, we presented a classifier that can predict non-genotoxic carcinogenicity by using short term exposure assays. In this approach, dose level is critical when evaluating chemicals at early time points.

• The Plant Pathology Journal
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• 제26권3호
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• pp.273-279
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• 2010

We evaluated 209 Capsicum accessions from the National Agrobiodiversity of RDA, for their reaction against of anthracnose disease caused by Colletotrichum acutatum. Two hundred nine accessions of Capsicum were almost composed with Capsicum annuum var. annuum originated from 37 countries. The percentage of infection due to C. acutatum ranged from 11.1% to 100% on immature and matured pepper fruits at 21 days after inoculation. On immature fruits of pepper, one hundred seventy three accessions of tested pepper were found infected with C. acutatum. Out of the 173 accessions, eighty five accessions were susceptible to anthracnose with dark brown to black lesions and slowly increased in size at 21 days after inoculation. Only thirty six accessions showed resistance against C. acutatum. On mature fruits of pepper, one hundred ninety eight accessions were infected with C. acutatum at 21 days after inoculation. Twenty one accessions showed a resistance reaction against C. acutatum. The results of this work indicated that all of resistance accessions to C. acutatum were have a genetic potential for the resources of resistance can be further used in pepper breeding programme against anthracnose and also demand more detailed investigation in this.